Scanline creates a virtual Megalodon. © Scanline Production GmbH.

Computational simulation is growing daily in importance to the VFX world. Yet those of us who are artists in the field mostly have no clue how simulations work; we just set the parameters and keep tweaking until we get it right. But the clockwork beneath those simulations arises from a complex synergy of ideas from absurdly brilliant minds.

Although there are dozens of people creating advances in computational fluid dynamics — the simulation of gases and liquids — I’ve chosen to look at two leaders of the pack. One is a distinguished American assistant professor at Stanford University, Ron Fedkiw, who just received the Significant New Researcher Award at SIGGRAPH 2005. The other is a distinguished German vfx filmmaker and head of Scanline Studios in Germany, Stephan Trojansky. The former comes from an academic/engineering background, while the latter hails from a practical filmmaking one. Each in his own way is a special genius leading the way. Both have artistic vision to go along with their technical prowess.

Why is fluid dynamics so important to the VFX world? In the simplest sense, the things we can realistically simulate with the best fluid dynamics are very expensive to duplicate practically. Both water and fire effects are difficult to manage, time consuming to set up and can be dangerous to actors. Plus, water is usually cold, causing nipple pucker and whining on the set.

By combining limited practical with extensive digital effects, everybody benefits. Since big ocean effects, massive explosions both terrestrial and in outer space, are very much in vogue, computational simulation of fluid dynamics is expanding what is possible, while reducing costs and danger for this entire class of shots. Unfortunately, up until very recently, digital water — and especially explosions — has been woefully detectable by ordinary human eyes. We have been suspending disbelief, but only just barely. All this has now changed.

The point of computational simulation is to push beyond the detectable into the realm of transparency. Water effects that you can’t tell from real require much more than technical algorithms; they require an eye for the real world, reference footage study and a great deal of technical artistry — which is no longer an oxymoron.